Hello everybody, Here is my 1957 M21 starting after ? years dark. I got a frame and engine (frozen) from a friend and worked on it over the last six months to get it to this condition.

1957 M21 Starting


I tried to start it last Thursday, and did, but had no oil pressure at all. Found out the oil spindle was sheared - and the oil pump had frozen - so I probably sheared it months ago and just realized it. Thanks to my friends at British Only in Michigan USA I had the part in two days, put it back together and we have ignition.

Simon had suggested I post here also because I used a non-standard Japanese Keihin carb 28mm. I'm sure that a Mikuni would work just as well.

Keihin PWK 28mm Carb

Keihin PWK 28mm Carb Exploded View

I hate to say it but all I had to do was put it on, no adjustment, I fiddled with the throttle screw but that's it, and it cost about $30 USD delivered in the US. Just something to think about if you want a cheap alternative sitting on the shelf. I do plan on getting a correct AMAL as I continue to bring it back the way it was. At least this will get me on the road as I find fenders, carb, seat cover, handlebars, controls, headlight, and the list goes on and on. But she is just about street legal in the states and just in time for summer.

I have posted here before and want to take this time to thank all those that responded - thank you again friends and hope to meet you one day!

It sounds healthy Jack it should do up nicely. I just finished a ZM21 1949 frame 1951 Engine Outfit, took it out for a test ride with my son, and when it was under load and hot the motor locked up. Pulled the engine down, and found out that I did not ream out the gudgeon pin bush enough, causing the piston to score the cylinder. Good news is its fixable. When it was going it pulled the sidecar like it was made for it. Hope to be back out on the road soon. thanks for the scoop on the carby, I bought a more concentric carry, but I like it better then the pre- mono block Amal carbys'.

Amazing how these old bikes even run without any petrol!!

They don't run long that's for sure!!!!

Great sound there!

I take it you have the standard jetting for the carb?

Hello Simon, Yes, I have other jets that came with the carb just left the standard in. Today I put on the horn, literally one bolt at a time! I ordered another battery plate, my homemade job was thrashing around way to much!

If you could tell us the jet and needle sizes that would be really helpful!

email (option): cas.vanderwoude@gmail.com

Well first look at the plug shows a nicely burning engine, I would expect nothing less!

I installed the chain today and will look for a window for a test ride. It's about 10 PM here now and just got the chain done, I will make no friends starting her now! For the carb, here are the sizes (I think). It has a starting circuit, not a choke. The links have the technical info and here it is also:



http://www.keihin-na.com/aftermarket/pwk/